The invention discloses a catalyst used for synthesis of C2 to C25 high carbon primary alcohol by CO hydrogenation, and a preparation method and application thereof. According to the method, carbon nanotubes are used as a carrier; active components are cobalt-containing compounds; auxiliary agents can also be added, and the auxiliary agents contain at least one compound selected from the group consisting of halide, oxygen chloride, sulfate, oxysulfate, carbonate, nitrate, oxynitrate, nitrite, oxalate and citrate of one element selected from the group consisting of lanthanum, zirconium and copper; the weight percent of the active components is 1 to 30% and the weight percent of the auxiliary agents is 0.1 to 10%; the specific surface area of the carrier is 20 to 600 m<2>/g and the apertureis 1 to 45 nm. The catalyst active components and the auxiliary agents are loaded on the carbon nanotube carrier by the processes of impregnating and the like. The catalyst has a high CO conversion rate and selectivity of higher alcohol when used for one step method of direct synthesis of higher alcohol by CO hydrogenation.